MAPLEWOOD - The man who leaked thousands of pages of top secret documents to the media in 1971 to expose the U.S. government's handling of the Vietnam War warned Saturday that another terrorist attack could permanently damage civil liberties.

Daniel Ellsberg, the former U.S. intelligence official responsible for leaking the so-called Pentagon Papers to The New York Times and 18 other newspapers, told an audience of about 400 that the Bush administration most likely would respond to any terror attack on U.S. soil by severely restricting freedom of the press and the individual's right to speak out.

"In a time of fear, I believe that the majority of the American people will cling to authority," Ellsberg told the gathering at Columbia High School for New Jersey Peace Action's annual luncheon.

"And if there is another terror attack," Ellsberg added sarcastically, "I believe the president will get what he wants. And what he wants is a new Patriot Act, one that will make the current Patriot Act look like the Bill of Rights."

The Patriot Act, originally passed by Congress after the Sept. 11, 2001, terrorist attacks, is up for renewal.

To combat terrorism, it gave law enforcement leeway into probing the private lives of Americans - allowing for easier wiretaps, incarceration without charges, monitoring of computer use and even checking on books borrowed from libraries. Some members of Congress expressed alarm recently that the FBI had initiated 30,000 investigations of private e-mail accounts last year.

Now the Patriot Act is up for renewal, and the Bush administration is seeking even tougher measures. Ellsberg, 74, said he worries that with the Iraq war at a stalemate, a terrorist attack on American soil was "not just possible, but highly likely." Were that to happen, Ellsberg predicted that Bush would respond by escalating the war on terror - possibly to include military action against Syria or Iran - while pushing for harsher restrictions against dissent at home.

Ellsberg said that as part of Patriot Act revisions, Bush most likely would push for an Official Secrets Act - one that would make it a crime for whistle-blowers to reveal government secrets to the public. And he added, such a ban probably would apply to journalists as well.

Ellsberg worked as an analyst for the RAND Corp. in the 1960s, which conducted a huge study of U.S. policy in Vietnam. That study, which was top secret and eventually numbered 7,000 pages, is the story of what went wrong in Vietnam. Once leaked to The Times, the document became known as the Pentagon Papers, and it told of the official lies by the Johnson and Nixon administrations that the war in Vietnam was winnable.

The Nixon administration tried to prevent publication of the Pentagon Papers, but the U.S. Supreme Court sided with the public's right to know. Ellsberg eventually stood trial for leaking official secrets, but the government eventually dropped the case.

Ellsberg said Saturday that he had grave doubts he would enjoy the same freedom today.

"I don't think the current Supreme Court would see it that way," he told the audience. He added that should an Official Secrets Act be adopted, "leaks would be a thing of the past."

He drew parallels between the Valerie Plame affair and the beginning of the Vietnam War. Plame was outed as a CIA agent after her husband, Joseph Wilson, a former U.S. ambassador, said the Bush administration lied about the reason for the invasion of Iraq. Wilson disputed the administration's claim that Saddam Hussein had attempted to purchase uranium from Niger to make nuclear weapons.

Ellsberg pointed out that the government said the Johnson administration also lied about the second Gulf of Tonkin incident on Aug. 2, 1964. At the time, President Lyndon Johnson claimed that a U.S. destroyer had been attacked by a North Vietnamese patrol boat in the Gulf of Tonkin, but Ellsberg said the incident never happened.

Ellsberg said that like Vietnam, America was in for a long war in Iraq, one that could possibly spread around the Middle East. "There are other wars ahead, and a long way to go," he said.

Members of the audience gave Ellsberg a standing ovation at the end of his hourlong presentation. As he hurried out the door to catch a train, attendees were left to contemplate what to do after the applause died down.